Comparing different methods for trapping mated queens of weaver ants (Oecophylla longinoda; Hymenoptera: Formicidae)

Abstract

The predatory efficiency of African weaver ants Oecophylla longinoda and their utilisation in protein production is a function of ant abundance. Reliable control of insect pests in tropical crops is achieved when ant populations are constantly high. Transplanted populations of weaver ant colonies containing egg-laying queens are more stable than those without. Achieving such stability through collection of colonies established in the wild is usually difficult because of uncertainty in locating the nest containing the egg-laying queen. In this study, we investigated four methods that may be used to collect mated queens that subsequently can be used to stock ant nurseries. The catch efficiencies of (1) leaf traps, (2) paper traps (both types providing a refuge for founding queens), (3) random search for queens and (4) light trapping were compared. Light trapping was the most efficient way to collect queens followed by leaf traps, random search and, last, paper traps. Light trapping and random search, though, required the presence of a person throughout the ant's mating season (several months), whereas this was not required when using leaf and paper traps.

Estimation of worker population size-density by nest counting in the Asian weaver ant, Oecophylla smaragdina (Formicidae: Formicinae) and its dynamic in oil palm plantations industry

“…We randomly set a 500 m transect along a path in the plantation (Exélis and Idris, 2013;Exélis, 2015). This transect crossed the territories of four matured O. smaragdina colonies (marked by the first emergence of reproductive caste (Rwegasira et al, 2015;Nielsen et al, 2016) from the same age and height of palm trees. The antagonism test was performed to distinguish between different colonies.…”

Location and external characteristics of the Oecophylla smaragdina queen nest

“…Three modes of weaver ant establishment in plantations are recognized: (1) naturally by newly mated queens and by colony migration and expansion from surrounding vegetation (Van Mele and Cuc 2000); (2) artificially by trapping and relocating newly mated queens, and boosting early colony growth by transplanting conspecific brood (Peng et al 2013;Rwegasira et al 2015); and (3) artificially by relocating entire mature colonies or fragments thereof (Peng et al 1998b;Van Mele and Cuc 2007). When mature colonies are used, it is crucial to locate the gravid queen (Peng et al 1998b).…”

The use of light to enhance weaver ant Oecophylla longinoda Latreille (Hymenoptera: Formicidae) queen catches

“…To arrest queens and increase their survival the application of artificially curled leaves have been used to ease the collection of founding queens. By providing such nests, collection success can be increased up to 100-fold compared to simple visual searches of plant foliage, and even with less time expenditures (Rwegasira et al, 2015a).…”

“…This is in contrast to O. smaragdina, which perform the flights at sunrise . Since O. longinoda perform flights just before nightfall, high numbers of queens are attracted to light sources right after the flight (Rwegasira et al, 2015a). Based on this, we hypothesized that a light source could be used to further increase the collection success of founding queens if combined with artificial nests.…”

“…Further they can be used to supply laboratories with colonies used in research and education. This is especially important as it is difficult to detect the single nest with the maternal queen(s) in weaver ant colonies as queen nests are small, placed high in the canopy, and are one out of up to several hundred nests per colony (Peng et al, 1998;Van Itterbeeck et al, 2015) Weaver ant queens disperse under their nuptial flight which takes place during rainy seasons (Nene et al, 2015;Nielsen et al, 2015;Rwegasira et al, 2015a;Rwegasira et al, 2015b). After mating they search for suitable nesting sites which under natural conditions are overlapping or curled leaves on host plants placed outside established weaver ant territories.…”